Stepped-plate ultrasonic transducer used as a source of harmonic radiation force optimized by genetic algorithm

Ultrasonics ◽  
2021 ◽  
pp. 106505
Author(s):  
Guilherme V. Selicani ◽  
Flávio Buiochi
2014 ◽  
Vol 104 (12) ◽  
pp. 123702 ◽  
Author(s):  
Wenjuan Qi ◽  
Rui Li ◽  
Teng Ma ◽  
K. Kirk Shung ◽  
Qifa Zhou ◽  
...  

2021 ◽  
Author(s):  
Sangnam Kim ◽  
Sunho Moon ◽  
Sunghoon Rho ◽  
Sangpil Yoon

AbstractEven though ultrahigh frequency ultrasonic transducers over 60 MHz have been used for single cell level manipulation such as intracellular delivery, acoustic tweezers, and stimulation to investigate cell phenotype and cell mechanics, no techniques have been available to measure actual acoustic radiation force (ARF) applied to target cells. Therefore, we have developed an approach to measure ARF of ultrahigh frequency ultrasonic transducers using theoretical model of the dynamics of a solid sphere in a gelatin phantom. To estimate ARF at the focus of 130 MHz transducer, we matched measured maximum displacements of a solid sphere with theoretical calculations. We selected appropriate ranges of input voltages and pulse durations for single cell applications and estimated ARF were in the range of tens of pN to nN. FRET live cell imaging was demonstrated to visualize calcium transport between cells after a target single cell was stimulated by the developed ultrasonic transducer.


2002 ◽  
Vol 24 (3) ◽  
pp. 129-138 ◽  
Author(s):  
Kathryn Nightingale ◽  
Rex Bentley ◽  
Gregg Trahey

Acoustic Radiation Force Impulse (ARFI) imaging is a method for characterizing local variations in tissue mechanical properties. In this method, a single ultrasonic transducer array is used to both apply temporally short localized radiation forces within tissue and to track the resulting displacements through time. In an ongoing study of the response of tissue to temporally short radiation force excitation, ARFI datasets have been obtained of ex vivo tissues under various focal configurations. The goal of this paper is to report observations of the response of tissue to radiation force and discuss the implications of these results in the construction of clinical imaging devices.


2007 ◽  
Vol 353-358 ◽  
pp. 3035-3038 ◽  
Author(s):  
Zong Wei Fan ◽  
Keji Yang ◽  
Zi Chen Chen

For applying acoustic radiation force to manipulate biomaterials such as cell, DNA, bio-macromolecule without contact, stationary sound field of an ultrasonic transducer was computed numerically. With the numerical data about the sound field, spatial distribution of the acoustic radiation force was analyzed. Besides the radiation force in the axial direction, trapping forces in the lateral direction were discovered. By moving the reflector continuously and carefully, positions of trapping wells were changed simultaneously, as the result, non-contact manipulation of micro cells was implemented.


2011 ◽  
Vol 474-476 ◽  
pp. 1808-1812
Author(s):  
Bo Fu ◽  
Yi Jing ◽  
Xuan Fu ◽  
Tobias Hemsel

The multi-objective optimal design of a piezoelectric sandwich ultrasonic transducer is studied. The maximum vibration amplitude and the minimum electrical input power are considered as optimization objectives. Design variables involve continuous variables (dimensions of the transducer) and discrete variables (material types). Based on analytical models, the optimal design is formulated as a constrained multi-objective optimization problem. The optimization problem is then solved by using the elitist non-dominated sorting genetic algorithm (NSGA-II) and Pareto-optimal designs are obtained. The optimized results are analyzed and the preferred design is proposed. The optimization procedure presented in this contribution can be applied in multi-objective optimization problems of other piezoelectric transducers.


2017 ◽  
Vol 74 (3) ◽  
pp. 79-86
Author(s):  
Leona von Köckritz ◽  
Andrea De Gottardi

Zusammenfassung. Im klinischen Alltag werden häufig erhöhte Leberwerte beobachtet. In der Regel erfordern sie weitere Abklärungen bezüglich der möglichen Ätiologie und des Schweregrad einer akuten oder chronischen Lebererkrankung. Die Abklärung sollte dabei neben einer gezielten Anamnese und sorgfältigen klinischen Untersuchung, auch die Bestimmung von laborchemischen Markern für Cholestase und Leberfunktionsstörungen (wie Alkalische Phosphatase, gamma-Glutamyltransferase, Bilirubin, Albumin und Gerinnungsfaktoren) umfassen. Die Bestimmung weiterer Parameter wie Ferritin und Transferrinsättigung, Autoimmunantikörper, Virusserologien, alpha-1 Antitrypsin und Coerulolasmin können weitere Hinweise für die kausalen Zusammenhänge der Leberfunktionsstörung liefern. Bei Patienten mit Lebererkrankungen ist eine sonografische Beurteilung der Leber obligat. Ergänzend zur Sonografie werden heute weitere nicht-invasive Methoden wie Fibroscan, Acoustic Radiation Force Impulse Elastometrie und Magnet-Resonanz-Elastografie zur Beurteilung der Leberfibrose eingesetzt. In ausgewählten Fällen ist eine Leberbiopsie notwendig, um den Grad der Fibrose und die Ätiologie der Lebererkrankung zu eruieren. Mithilfe eines Fallbeispiels, diskutieren die Autoren im Folgenden die rationale Anwendung diagnostischer Tests und deren korrekte Interpretation und schlagen eine Orientierungshilfe zur rationalen Abklärung von Patienten mit Lebererkrankungen vor.


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